A Levels Biology (9700)•9700/13/O/N/20

Explanation
Prokaryotic Cell Membrane Composition
Steps:
- Identify prokaryotic cell surface membrane as a phospholipid bilayer.
- Confirm phospholipids form the basic structure of the membrane.
- Note proteins are integral components embedded in the bilayer for functions like transport.
- Distinguish peptidoglycan as a polymer in the cell wall, not the membrane.
Why B is correct:
- Prokaryotic membranes consist of a phospholipid bilayer with embedded proteins, per standard cell biology definitions.
Why the others are wrong:
- A includes peptidoglycan, which is a cell wall component, not membrane.
- C excludes proteins, which are essential membrane elements.
- D excludes phospholipids, the core of the lipid bilayer.
Final answer: B
Topic: Fluid mosaic membranes
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